Process of producing flat drying, wet crease resistant cellulosic fabrics by reaction with cross-linking agents and products produced thereby



United States Patent ice 2,985,501 PROCESS OF PRODUCING FLAT DRYING, WET CREASE RESISTANT CELLULOSIC FABRICS BY REACTION WITH CROSS-LINKING "AGENTS AND PRODUCTS PRODUC'ED THEREBY Dmitry lVL Gagarine, Pendleton, S.C., assignor to Deering Milliken Research Corporation, Pendleton, S.C., a corporation of Delaware 1 No Drawing. Filed Apr. 3, 1956, Ser. No. 575,716

. -19 Claims. c1. 8-120) This invention relatesto modified cellulose yarns and fabrics having an improved configurational memory, and to methods formaking the same, More particularly the invention relates to modified cellulose yarns and fabrics having an improved tendency to return to an original fiat, creased or the like co guration when washed and thereafter dried." I

It is wellknownthat fabrics can be formed which have a tendency to return to a predetermined configuration after washing. For example, by applying certain resins to fabrics'an'd curing the resin while the fabric is in a flattened condition, one can obtain afabric that, when allowed to dry inaflat condition, has a pressed appearance and requires no ironing." ln'a similar manner, one can form permanent pleats in a fabric so that the pleats are not removed by washing, the fabric dries flat between creases, and no ironing of the fabric is required. Any such fabric, or yarns capable of jresulting'in such fabrics, are referred toin this specification as flat drying and it will be' understood that this term is employed broadly to include any textile material which normally requires no ironing, pressing or the like for a satisfactory appearance. 1

Fabrics which gain their fiat drying properties as a result of resin application have several disadvantages but the primary disadvantage is that the resin application results in yellowing and the fabrics cannot be readily bleached. Resin treated fabrics absorb chlorine during bleaching with conventional bleaches and the absorbed chlorine results in degradation and further discoloration. Other disadvantages of resin treated fabrics are that they generally cannot be comfortably worn in contact with the body and the flat drying characteristics are frequently not so pronounced as is usually considered desirable.

Fabrics woven of certain synthetic materials, such as glycol terephthalate fibers, also display flat drying qualities but such fabrics likewise have several inherent disadvantages. For example, flat drying polyester fabrics are expensive, have a tendency to collect static electricity, and, if formed from staple fibers, generally display a tendency to pill badly. In. addition, polyester fabrics have a low moisture absorbitivity so that they feel cold to the touch and are incapable of absorbing perspiration from the body. Still another disadvantage is that they become dingy after repeated washings and cannot be readily bleached.

It has now been found that modified cellulose yarns or fabrics having excellent fiat drying characteristics and free of the disadvantages mentioned above can be formed by reacting, while in a swollen condition, the cellulosic fibers of the yarns or fabrics with a cross linking agent such that the cross linkage includes a chain of at least three carbon atoms. Suitable cross linking agents include those capable of being represented by one of the formulae:

- group of the formula -RY-RY- 2,985,501 Patented May 23, 1961 wherein X represents halogen, R R and R represent, in each instance, a member selected from the group consisting of hydrogen and mono-valent, non-functional radicals, R represents a divalent connecting radical and Z, in each instance, represents a divalent radical selected from the group consisting of those capable of being represented by one of the formulae:

wherein R and R in each instance, represent hydrogen or a monovalent, non-functional radical, and X represents halogen.

R R R and R in the above formulae, in'each instance, preferably represent hydrogen since such compounds are the most readily prepared but they can in one or more instances represent lower alkyl groups such as methyl or ethyl, hydroxyalkyl groups such as hydroxymethyl or hydroxyethyl, monocyclic aryl groups such as phenyl or tolyl, cycloalkyl groups such as cyclohexyl, haloalkyl groups such as chloromethyl' and chloroethyl, or R and R can together represent a divalent connect-. ing radical such as a methylene oran ethylene radical. The only requirement is that R R R and R must not be-such as to prevent the compound from reacting with at least one hydroxy group in two different cellulose molecules. R, can represent any divalenteonnecting group but in most instances will represent either an alkylene group such as methylene, ethylene or propylene, a hydroxyalkylene group such as hydroxypropylene or a wherein Y represents oxygen or sulfur, R and R" represent lower alkylene groups such as methylene or ethylene and R represents any divalent connecting radical as illustrated by a lower alkylene group, a lower hydroxyalkylene group such as 2-hydroxypropylene, a monocyclic aryl radical such as phenyl or tolyl, a radical of the formula wherein n represents an integer of from 1 to about 5 and R represents a divalent hydrocarbon radical as illustrated by I Compounds of the latter type result when epichlorohydrin is reacted with less than an equal molar quantity of a dihydric alcohol or phenol. It should also be mentioned that when across linking compound corresponding to one of the formulae in the preceding paragraph contains two Z groups, the groups may be the same or different. Specific illustrative examples of suitable cross linking compounds are: 1,3-dichloro-2-propanol, 2,3-dichloro 1 propanol, '2,3-dibromo-1-propanol, m-di({3,'yepoxypropoxy)benzene, 1,3 di('fi hydroxy-'y-chloropropoxy) 2-propanol, l,2-di(B-hydroXy-y-chloropropoxy)- ethane, 1,2-di(;9,' -epoxypropoxy)ethane, 1,2;3,4-diepoxybutane, 1,2;5,6-diepoxyhexane, 1,5-dihydroxy-2,4*dich1oro-cyclohexane and 2,6-dichloro-3,4,5-trihydroxy-5-hydroxymethylheptane. The preferred cross linking compounds are 1,3-dichloro-2-propanol, 2,3-di chlorol-propanel, and mixtures of the two.

It has been previously suggested that certain compounds of the above type be reacted with cellulose fibers but in each instance the reaction has been carried out under such conditions that no appreciable flat drying properties were imparted to the treated textile materials. For example, in US. Patent 2,730,427 it is suggested that various diglycidyl ethers be reacted with dry cellulosic materials at elevated temperatures. While such a process may result in some cross linking of the cellulose molecules, the desirable flat drying characteristics of the fabrics produced by the process of this invention, i.e., high wet crease resist ance, are not imparted to the textile materials to any appreciable extent presumably because the reaction is not carried out upon the fibers while they are in a swollen condition. It is also suggested in U.S. Patent 1,741,637 that epichlorohydrin may be reacted with cellulose fibers but the process of this patent results in substantially no flat drying characteristics being imparted to the textile material since, among other reasons, the reaction is carried out under such conditions that little or no cross linking is achieved. According to the process of the US. Patent 1,741,637, the epichlorohydrin is partially hydrolyzed so that in place of cross linkage of the cellulose molecules, one largely obtains dihydroxypropyl cellulose'etliers.

The textile materials according to this invention have many advantages, a, primary one of which is that they may readily be produced in white shades which remain white after repeated washing. The chlorine retention of the new modified cellulose material is exceedingly low and the fabrics may be repeatedly bleached with chlorine bleaches without injury or discoloration. In fact, modification of the cellulose fibers according to this invention will actually protect them from damage which would ordinarily result from the use of excessive quantities of chlorine bleach. Additional advantages, are that the new textile materials may be inexpensively produced, have a faster drying rate than untreated cottons and have an increased luster as compared to cotton. The moisture regain of the new modified cellulose textile of this invention is approxi mately 8% so that the fabric feels warm to the touch and readily absorbs perspiration when worn next to the body. The flat drying properties of the new fabrics are excellent and the fabric does not have to be drip dried but can be washed in a washing machine, extracted in a centrifugal dryer or passed through squeeze rollers, and thereafter dried on a hanger or the like.

As previously mentioned, the cross linking must be effected whilethe cellulose fibers are in a swollen condition so that the reaction must be conducted in the presence of a swelling agent such as water. The amount of moisture present during the reaction has been found to be critical since, if too little moisture is present, adequate swelling of the fibers is not obtained and if too much moisture is present, intimate contact of the cellulose fibers with the cross linking agent is difiicult to achieve. Even so, however, the amount of moisture present may be varied within wide limits, depending upon the conditions of reaction, as will be more fully explained in subsequent paragraphs.

To accommodate the swelling agent, it is necessary that the cross linking reaction be conducted at a relatively low temperature and in order for the reaction to be effected at low temperatures, it is necessary that one employ a suitable catalyst. The preferred catalyst for the cross linking reaction is sodium hydroxide, although other bases, as illustrated by-potassium hydroxide or other alkali metal hydroxides, materials which form alkali metal hydroxides in aqueous solution as illustrated by sodium silicate and sodium sulfide, and quaternary ammonium bases such as trimethylphenylammonium hydroxide, may also be employed. The amount of the catalyst employed is important in all instances since highly concentrated basic aqueous solutions result in the hydrolysis of the functional groups of cross linking agents of the type which are suitable for use in this invention and if the concentration of the base is too great, hydrolysis' of the'cro'sslinking agent will occur to such an extent'that a satisfactory degree of 'cross.link ing will not be obtained. In some instances, the limiting factor is not the hydrolysis 'of the cross linking agent'but rather is the concentration of base that can be tolerated by the cellulose and if one is processing, for example, re-

4 generated cellulose fibers, it is generall advantageous to retain the base concentration 'below about 7%. On the other hand, the amount of base employed, on a dry weight basis and calculated as NaOH, should generally be at least about 2% by weight of the water present since basic solu tions of a lower concentration frequently may not have sufiicient catalytic effect to result'in the desired degree of cross linkage. If the reaction -results inane formation, the minimum amount of base which may satisfactorily be employed, on a dry weight basis,-is increased by the amount necessaryto neutralize the acid formedin obtaining a satisfactory degree of cross linkage and this is especially true ,when part of the acid may be formed before any cross linkage is accomplished. The preferred amount of base to be employed is generally from about 5% to 15% by weight of the water present during the reaction. The amount of base employed, on a dry weight basis, also affects the amount of water that may be present during the reaction for reasons other than the fact that a proper eflective base concentration is required. If one attempts to conduct the cross linking reaction in the pres ence of a large quantity of a concentrated aqueous basic solution, the cross linking agent is largely prevented from gaining intimate contact with the cellulose molecules so that an adequate degree 'of cross linkage is'notobtained. The amount of the solution employed should be such that the total water present is equal to notmore than about 130% and preferably not more than of the dry weight of the cellulose. Regardless of the weight 'of base employed, it is difficult, if not impossible, to obtain satis-' factory results if the total water present is equal to more than about of the weight of the textile material. on the other hand, at least enough water should be present to result inthe cellulose being swollen 'toja near maximum extent and to permit the base to be "evenly distributed throughout the yarn or fabric. These considerations gene'rally require that an amount of waterequal to at least about 15 to 20%o'fthe 'dry weightof cellulose be present, and preferably, the amount of water present inthe yarnor fabric during the cross-linking reaction is 'equal to from about -30% to 100% of the weight of the cellulose.

The amount 'of the cross linking agent "employed may be varied within wide limits under certain conditions but there is'preferably employed a weight of the cross linking agent equal to from about 6 to 30% of the weightof cellulosic fibers. This generally results in the cellu'losic fibers gaining from about '3 'to 4% in "weight 'If one attempts to employ 'an amount of thecr'o'ss linking agent appreciably outside of the above preferred range,numerous unexpected difficulties will frequently/"be encountered. For example,if one attempts 'to 'einploy' les's than about 5% of the cross linking agent, it will frequently "be found that objectionable side reactions are encounteredand'even though the increase in weight by the cellulose fibers may be only slightly less than when employing a preferred amount of the cross linking agent, tliefiat drying tendenc ies of the finished fabric may be"grea tly diminished or nonexistent. Under very favorable 'coiiditidns, how ever, it is possible to obtain flat drying properties when employing only about 2 to 3% by weightfo'f the cross linking agent and with an increase in weight of only about 1% by the cellulosic fibers. If one attempts to increase the amount ofthe cross linkingag ent appreciably above the preferred range, objectionable side reactions are usually encountered, a corresponding increase in weight is not achieved, the finished fabric may not'display the same high measure of flat "drying properties as when a preferred amount of the cross linking agent is employed and the finished fabric may be unnecessarily low in tensile strength. Under so'rne'conditions one'will. achieve substantially no cross linking at all. Fer example, if one is employing a crosslinking agent which mustsplit out acid before 'beingin a suitable form for reaction with the cellulose, all of the base present in the fabric may well be utilized in transforming the cross aesasoi linking agent into a suitable form for reaction and if one attempts to add sutficient excess base to compensate for the acidformed, it may be found that this requires increasing the base concentration beyond operable limits. For example, one experiences such a result when attempting to employ a very large quantity of one of the dihalopropanols as a cross linking agent. With some cross linking agents and under suitable conditions, however, it is possible to employ an amount of the cross linking agent equal to as much as about 100% of the weight of the cellulose.

The new process can be satisfactorily performed with yarns or fabric containing either natural cellulose fibers, regenerated cellulose fibers or modified cellulose fibers having a portion of the hydroxy groups therein blocked by ester or ether groups. Examples of materials of the latter type which can be employed include yarn or fabrics composed of cellulose actate or methyl cellulose fibers. Generally, however, the cellulosic fibers should have an average of at least about 1.8 free hydroxy groups per glucose unit, and cellulosic materials having a smaller number of free hydroxy groups do not give satisfactory results even though, in the case of cellulose esters, the ester groups might theoretically be removed by hydrolysis during the cross linking reaction. Satisfactory results can also be achieved with yarns or fabrics partially composed of other than cellulosic materials and this is particularly true if the non-cellulosic fibers have some flat drying properties of their own. For example, the flat drying tendencies of a yarn spun from a mixture of glycol-terephthalate fibers and cotton fibers can readily be increased by theprocess of this invention, even if the percentage of cotton fibers is as small as, for example, 10% Even when the non-cellulose fibers display no flat drying properties, yarns or fabrics containing the same can be caused to display flat drying properties by the new process if the yarns or fabrics contain at least about 40% by Weight of cellulosic fibers.

All of the chemical reactions which are or may be involved in the new process are not fully understood but it is presently believed that the reaction, in almost all instances, is at least partially accomplished throughthe NaOH (4) +cellulose-O H celluloseO-CHg-C HCHzO-ellulose Compound (5) is the desired product and the product that is largely obtained by the process of this invention. It will be understood, however, that there are side reactions which may become completely predominant if the specified conditions are not observed. For example, one series of side reactions that may be obtained can be represented by the following equations starting with epichlorohydrin or compound (2) above:

01 o 01 OH OH g} g NaOH I I Hz-C CHz- CHg-CHCH1 OH OH OH tions that a minimum amount of this or any similar byproduct is obtained.

In view of the fact that it is believed that the reaction, when employing a halohydrin cross linking agent, most likely proceeds through epoxy intermediates, it is indeed surprising that the epoxy cross linking agents and the halohydrin cross linking agents are not full equivalents It is a general rule that reacting cellulose fibers with cross linking agents reduces their tensile strength and the cross linking reactions of this invention are not exceptions/to the rule. The extent of the loss in tensile strength, however, is normally appreciably less whenemploying the halohydrin cross linking agents than when employing the epoxy cross linking agents. The reasons for this are not fully understood but it is believed that the halohydrin cross linking agents become better distributed within the cellulosic fibers and that this results in a more uniform cross linking reaction with a reduction in the intensity of side reaction. This would not only prevent a large portion of the cellulose molecules from being transformed into hydroxy alkyl cellulose ethers or the like but might also prevent certain localized areas of the fibers from becoming so highly cross linked that they are brittle and weak. The theory of improved distribution with the halohydrin cross linking agents appears to be substantiated by the observable fact that improved results are obtained with the epoxy cross linking agents when they are applied as a solution in a water miscible solvent.

The reagents may be applied to the fabric in any order or, by means of an emulsion, the reagents may even be applied simultaneously. If one is processing a dry material, it is generally advantageous to first apply the cross linking agent and, after a suitable period of time to allow the cross linking agent to become evenly distributed in the fabric, apply the base in the form of an aqueous solution of a proper concentration. In some instances, however, it may be more convenient to work with a wet fabric and if the fabric is wet, it is generally advantageous to apply the base and thereafter apply the cross linking agent. This allows the base to become diluted with the water in the fabric before contact with the cross linking agent and not only results in more uniform cross linkage of the cellulose but also reduces the intensity of side reactions.

With reference to the order in which the reagents are applied to the textile material, it has been found that the halohydrin cross linking agents, as illustrated by 1,3- dichloro-Z-propanol, and the epoxy cross linking agents, as illustrated by epichlorohydrin, are again not full equivalents. The halohydrin cross linking agents in undiluted form can be applied to dry cellulosic textile materials or to textile materials wet with a basic solution and in either instance excellent fiat drying properties with a negligible amount of wet slickness are imparted to the yarns or fabrics. The epoxy cross linking agents can readily be applied to dry textile materials with good results. An epoxy cross linking agent can be applied with good results to fabrics or yarns wet with a basic solution if the agent is first mixed with from about 20% to and preferably from about 30% to 60% by weight from the'reaction. exothermic andin most instances will cause a gradual rise in temperature as the reaction progresses "but this is not of a water miscible solvent such as dioxane or acetone. The reagents may be'applied in'anysuitable manner as illustrated by padding, spraying, brushing or the like. If the basic solution is to be applied first to either a wet or dry fabric, best results are usually obtained by immersing the fabric or yarn in a solution of the base and thereafter passing the textile material through squeeze rolls to remove excess liquid. If the base is to be applied subsequent to the cross linking agent, it is generally advantageous to apply the same by means of an applicator roll or, in other words, by passing the textile material into contact with a portion of the surface of a roll having another portion of its surface in contact with a supply of the solution to be applied. This eliminates the possibility that a large 'per- .centage of the cross linking agent might be leached from the textile material and results in less hydrolysis of the cross linking agent than might be obtained by dipping the fabric or yarn into a large volume of the basic solution. The cross linking agent is in almost all instances best applied by means of an applicator roll because of the relatively small quantity of the agent which need be employed and because this method of application generally results in greater uniformity than spraying. Of course, if forsome reason one desires to employ a large excess of the cross linking agent, it will undoubtedly be found to be more convenient to employ a padding process.

The cross linking agents suitable for use in the new process are, in almost all instances, liquids so that they may be applied without difficulty but if one wishes to employ a solid cross linking agent, it is only necessary to employ a suitable inert solvent as may be illustrated by petroleum ether, toluene, benzene, carbon tetrachloride '-tion on the textile material is difficult to achieve, an inert diluent, such-as the solvents mentioned above, may be added to reduce the viscosity or increase the volume.

In some instances it may be dmirable to add small amounts of a non-cross linking material capable of reacting with the cellulose even though this frequent-1y reduces the extent .to which flat drying properties can be imparted to the yarn or fabric. For example, a weight of acrylonitrile, "equal to from-about 10 to 50% of the Weight of the cross linking agent, added to the cross linking agent results in a whiter fabric or yarn. It is also frequently advantageous to add a small quantity, for example, 1% to 30%,

of an aliphatic or cyclic polyhydric alcohol or phenol, as

illustrated by ethylene glycol, glycerine, and .sorbitol, to the cross linking agent since this results in some cross linkages of greater chain length and frequently increases the strength of the fabric or yarn without materially reducing its flat drying tendencies.

The bases employed in the new process are, in most instances, solids and are preferably applied in the form of an aqueous solution of a proper concentration to result in the fabric having a desirable final moisture content.

It is possible to use an organic solution of the base or a solution of the base dissolved in a mixture of water and organic solvent but such is seldom if ever advantageous.

The cross linking reaction may be conducted at any suitable temperature below about 110 C. but for reasons of convenience the reaction is preferably carried out at room temperature or the temperature naturally resulting The cross linking reaction is slightly generally detrimental and no means for retaining the reaction temperature at a constant level "are gner'suy :per minute. preferably of stainless steel and the lower part of the 8 necessary. The time required forthe cross linking reaction will vary somewhat with the temperature, the cross linking agent employed and the order in which the reagents are applied, but even at low temperatureaie. 20 to 30 C., good flat drying properties are normally obtained in only about 30 minutes to 1 hour and the reaction is reasonably complete in from about 3 to 6 hours. At 60" C., the reaction is, as a rule, reasonably complete in 10 minutes or less. Exceedingly long reaction times, for example, 48 hours or more, can be employedwithout loss of flat drying properties but one may find that the tensile strength of the fabric or yarn is reduced to an unnecessarily low level with such prolonged reaction periods and, for this reason, the cross linking reactionis preferably allowed to continue for only so long as is necessary for maximum flat drying properties. I g

The cross linking reaction tends to permanently fix the configuration of the fabric or yarn as that prevailing during the reaction. In other words, if one desires a fabric that will have a flat and pressed appearance after washing, it is necessary that the fabric be retained in a flat and slightly tensioned condition during the cross linking reaction. This can be accomplished by conducting the reaction while the fabric is in a tenter frame or by first passing the fabric through a short tenterfframe and thereafter rolling the same into a tight roll. If desired, the roll of fabric can be wrapped in a water impervious cover such as aluminumfoil or a sheet of vinyl plastic as illustrated by polyethylene plastic. Of course, if it is desired that the fabric display permanent pleats or the like, then it is necessary that the cross linking reaction be conducted while .the fabric is in a pleated condition. Thus the process of this invention can be conducted while the fabric is completely flat, i.e., smooth and free from extraneous wrinkles, -or while the fabric is in a pleated state but otherwise fiat, if this is the desired final configuration. 1

Following the cross linking reaction, the fabric or yarn should be thoroughly scoured employing any suitable-detergent. This not only serves to remove excess reactants but also decreases the wet slickness of the fabric and increases its flat drying tendencies. The latter effect is believed to be due to the removal from the fabric of byproducts as illustrated by dihydroxypropyl cellulose ethers, and, if desired, the fabric may even be given an alkaline wash to more effectively remove the alkali soluble dihydroxypropyl cellulose -ethers from the alkali insoluble cross linked components of the cellulosic fibers.

The invention will now be more specifically illustrated by the following examples in which all parts are by weight unless otherwise indicated.

Example I instance, of approximately 20 degrees and is drawn over the rolls with a linear velocity of approximately 40' feet The peripheral surface of the first roll is roll is allowed to contact, through an and about a quantity of a mixture consisting of approximately 70% 2,3-dichloro-1-propauol and 30% 1,3-dichloro-2-propanol. The roll is driven so that its upper surface is moving in the'same direction as the oloth'and the rate of rotation of the roll is adjusted so that there is deposited on the cloth about 15% by weight of the dichlorohydrin mixture which generally requires that the roll be rotated at such a rate that it has aperipheral velocity less than the linear velocity of the dry cotton material. The surface of the second roll is preferably formed of rubber and the lower part of the roll is allowed to contact, through an arc of about 90, a solution of sodium hydroxide, containing 2% sodium Z-ethylhexyl sulfate as awetting agent. The rate of rotation of the roll is adjusted so that there is deposited on the cloth approximately 70% by weight-of the basic solution. Following its contact with the second roll, the cotton material is passed through a short tenter frame and immediately thereafter is woundinto a tight roll. The roll of material is wrapped in a sheet of polyethylene plastic and is stored at room temperature for approximately 12 hours. The material is then unwound and vigorously secured in water containing 0.5 of a lauryl sulfate wetting agent (Duponol 80). Thereafter the material is rinsed in clear Water, extracted and dried on a tenter frame. The finished fabric displays excellent fiat drying qualities, an excellent white color and can be repeatedlybleached with chlorine bleaches without yellowing. The weight gain of the fabric, on'a dry weight basis, due to reaction with the halohydrin is approximately 3%.

This example represents a presently preferred procedure for processing dry fabrics. A slightly higher weight gain can generally be achieved by employing somewhat larger quantities of the cross linking agent and :base but the increase in flat drying tendencies or resistance to micro-organisms is not increased proportionally so that it appears that the use of higher quantities of halohydrin is not justified from an economic point of view.

Instead of employing the first roll for the application of the dichlorohydrin mixture, as in the above example, the first roll can be employed for the application of the sodium hydroxide solution and the second roll used'for the application of the dichlorohydrin, although the results are frequently not so satisfactory as when the dichlorohydrin is applied first. Likewise, instead of applying the reactants by means of rolls, they can be atomized onto the fabric by means of a sprayer or wicked onto the fabric by means of a pliable brush or the like. It is also possible to substitute other basic solutions for the sodium hydroxide solution employed above and one can, for example substitute with comparable results a 10% potassium hydroxide solution containing 4%. of 2-ethylhexyl sodium sulfate 'as a wetting agent, or a 10% solution of trimethyl phenyl ammonium hydroxide containing 1% lauryl trimethyl ammonium chloride as a wetting agent. 1

Example II A length of wet approximately 2.5 yards per lb. dry weight cotton material :eontaining approximately 70% by weight of water is passed through a pad box containing a quantity of sodium hydroxide. 'Ihe cloth is then passed through a pair of squeeze rolls to remove Example III Example II is repeated except that in place of a mixture of dichloropropanols, there is applied to the fabric an equal quantity of 2,3-dichloro-1-propanol. Equally excellent results are obtained.

Example IV Example II is repeated except that in place of a mixture of dichloropropanols, there is applied to the fabric an equal quantity of 1,3-dichloro-2-propanol. Equally excellent results are obtained.

Example V Example I is repeated except that in place of a mixture of dichlorohydrins, there is applied to the fabric an equal quantity epichlorohydrin and the rate of rotation of the second roll is adjusted such that only of the basic solution is apportioned onto the fabric. The finished fabric displays excellent flat drying properties.

excess moisture and tests at this point indicate that the 1 material contains approximately 75 to 80% moisture and about 7%NaOI-I on the weight of-dry cotton. Imme diately thereafter the material in open width is passed in contact with the upper peripheral surface of a stainless steel roll, the lower surface of which is in contact with a quantity of a mixture consisting of approximately 30% 1,3-dichloro-2-propanol and 70% 2,3-dichloro-l-propanol and the speed of the roll is adjusted such that, approximately 12% by weight of the halohydrin is deposited upon thefabric. The fabric is thereafter passed through 1 a short tenter frame and wrapped into a tight roll. The roll of material is then wrapped in a sheet of polyethylene plastic and allowed to stand for 18 hours following which time it is unwound and thoroughly scoured in water containing 0.5% of a lauryl sulfate wetting agent (Duponol 80). The material is then dried on a tenter frame and is found to have excellent flat drying properties and is an excellent shade of white.

This example represents a presently preferred proce- Example VI Example H is repeated except that in place of a mixture of dichlorohydrins, there is applied to the fabric about 25% by weight of a 50% solution of epichloror' hydrin in acetone. The finished fabric displays good flat drying properties.

Example VII A plurality of ends of 3l /2s cotton yarn are passed successively over a pair of rolls according to the procedure outlined in Example 'I. .The rate of rotation of the firstroll is adjusted to give .a pickup of approximately 15 of-epichlorohydrin and the second roll is adjusted to apply approximately 35% of a 10% sodium hydroxide solution. The yarn is collected on porous cores, placed. in a'metal container and allowed to remain foiapproximately 10 hours. The yarn is then scoured, dried an'dwoven into an square fabric. The fabric displays a high degree of flat drying properties and an excellent white color; a f

Example VIII Example V is repeated except that in place of epichlorohydrin there is applied to the fabric approximately 22% of a diepoxy compound resulting from the reaction of 2 moles of epichlorohydrin with 1 mole of a dihydric phenol of the formula: g g

v CH2 The fabric displays excellent flat drying properties.

Example IX Example V is repeated except that in place of epichloi rohydrin there is applied to the cotton fabric approxi- V 11 7 mately- 18% of an epoxy compound represented by the formula:

oH2 oH-CH-orn The finished fabric displays excellent flat drying prop erties.

, Example Xl Example II is repeated except that in place of a mixture of dichloropropanols, there is applied to the fabric approximately 18% of a compound prepared by reacting ethylene glycol with a large excess of epichlorohydrin and which is believed to be represented by the formula:

(mg-i:HoHr-oornom-oom-on-orn The finished fabric displays good fiat drying properties and has an excellent white color.

Example XII A plurality of ends of 31 /3s cotton yarn are passed successively over a pair of rolls generally according to the procedure described in Example I. The first of the two rolls isemployedfor the application of epichlorhydrin 'and the rate of rotation of the roll is. adjusted such that approximately 15% by weight of the cross linking agent is apportioned onto the yarn. The second roll is adjusted to apply approximately 35% of a sodium hydroxide solution, and immediately following contact with the second roll, the yarns arecollectively passed into a crimping chamber retained at a temperature of approximately 160 F. The size of the chamber is such that the yarns remain therein for approximately minutes. The yarn is then dried, scoured and collected. The thus treated yarn displays a highly elastic and lofty nature which is permanent to repeated washing. The yarn is then woven into an 80 square fabric. The fabric displays a very desirable crepe like appearance which, even when partially removed by ironing, is rapidly restored by wetting the fabric with water and is permanent for the life of the fabric.

ExampleXlII Alength of dry desized and mercerized about 2.4 yards per lb. material is passed successively over a pair of rolls as described in Example -I. By contact with the first roll there is applied approximat ly 15% by weight of epichlorohydrin and by contact with the second rollthere is applied approximately 40% by weight of a 10% sodium hydroxide solution containing 2% sodium 2-ethylhexyl sulfate as a wetting agent. Immediately following its contact with the second roll, the cotton material is passed through a pleater so that a plurality of V2 inch pleatsare placed in the fabric. The pleated fabric is thereafter wound into a tight roll, and the roll is wrapped in a sheet of polyethylene'plastic and stored at room temperature for approximately 12 hours. The material is then unwound and vigorously scoured in Water containing 0.5% of a lauryl sulfate Wetting agent (Duponol 80). Thereafter the material is rinsed in clear water, extracted and dried. The pleatedfabric is an excellent white color and has an excellent general appearance. A ladys skirt made from material prepared generally by the procedure of this example'has been washed and Worn approximately 40 times with no apparent loss of its tendency to form into pleats.

' Example XIV A, length of about 1.8 yards per lb. viscose rayon material is passed over a pair of rolls as described in Example I. By means of the first roll there is applied to the fabric by weight of epichlorohydrin and by means of the second roll there is applied to the fabric a A a '50% o'fa- 5-% potassium-hydroxide solution. The fabric is" thereafter passed through a short tenter frame and wrapped into a tight roll. The roll of material is then V 12 .7 wrapped in a sheet of polyethylene plastic and allowed to stand for 18 hours following which time it is unwound and thoroughly scoured in water containing 0.5% of a lauryl sulfate wetting agent. The material is then dried on a tenter frame and is found to have excellent fl at drying properties.

The procedure when employin'g other cross linking compounds or other bases is the same as is illustrated in the above examples.

Having thus described my invention, what I desire to claim and secure by Letters Patent is:

l. A processrfor imparting flat drying properties to a cellulosic fabric whose cellulosic fibers have an average of at least about 1.8 free hydroxy groups per glucose unit which process comprises applying to said fabric a total amount of water equal to at least 15 but less than by weight of the dry weight of the fabric, a strong base selected from the group consisting 'of alkali metal hydroxides, alkali metal salts which form alkali metal hydroxides in aqueous solution, and quaternary ammonium hydroxides, the amount of said base, on a dry weight basis and calculated as NaOH, constituting not less than about 2% by weight and not more than about 15% by weight of the total water present, and at least about 5% but not more than about 30% by weight of the cellulosic fibers of acellulose cross linking agent sellect'ed from the group consisting ofthose capable of being represented by one of the formulae:

wherein R is selected from the group consisting of hydrogen and, when taken with R a lower alkylene group, R4, represents a divalent connecting radical having from 3 to 46 carbon atoms, inclusive, selected from the group consisting of alkylene, hydroxyalkylene, and a group of the formula -RY-R'Y-- whereinY is selected from the group consisting of oxygen and sulfur, R. and R' are lower alkylene, and R is selected from the group consisting of lower alkylene, lower hydroxyalkylene, phenyl, tolyl, a radical of the formula C H (OC H wherein n is an integer from 1 to. about 20, and a radical of the formula wherein n is an integer from 1 to about 5 and R' is and Z, in each instance, represents a divalent radical se lected from the group consisting of those capable of being represented by one of the formulae:

wherein X, in each instance, represents halogen, R R R and R represent, in each instance, a mono-valent radical selected from the group consisting of hydrogen, lower alkyl, lowerhydroxyalkyl, phenyl, tolyl, cycloalkyl containing less than 7 carbon atoms, and lower haloalkyl; conforming said fabric, containing said base and said cross linking agent, to the configuration desired in the finished product in which, except for any pleats desired in the finished product, the fabric is flat; and retaining said fabric in said configurationfor a time suflicient to effect enough cross linkages of saidxcellu'losic: fibers. by said cross linking agent to produce a flat drying fabric,

thereby producing a material having fixed therein the configuration present during the reaction.

'2. Av process according to claim 1 wherein the-cross linking agentflis applied to the dry fabric and the base thereafter applied in the form of an aqueous solution.

3. A process according to claim 1 wherein the base is applied to the dry fabric in the form of an aqueous solution and the cross linking agent is thereafter applied.

4. The process of claim 3 wherein the cross linking agent comprises a dihalohydrin.

5. The process of claim 3 wherein the cross linking agent comprises 1,3-dichloro-2-propanol.

6. The process of claim 3 wherein the cross linking agent comprises a mixture of 1,3-dichloro-2-propanol and 2,3-dichloropropanol.

7. The process of claim 3 wherein the cross linking agent comprises epichlorohydrin.

8. The process of claim 3 wherein the cross linking agent comprises a compound of the formula:

9. A process for imparting flat drying properties to a textile fabric containing at least 40% cotton fibers so that the fabric will have a flat and pressed appearance after washing which comprises applying to the fabric from about 20% to 100% of the weight of the cotton fibers of an aqueous solution of an alkali metal hydroxide, the amount of said alkali metal hydroxide, on a dry weight basis and calculated as NaOH, constituting not less than about 5% by weight and not more than about 15% by weight of the total water present, and from 6% to 30% by weight of the cotton fibers of a cross linking agent comprising 1,3-dichloro-2-propanol and retaining the fabric in a flat condition for a time sulficient to effect enough cross linkages of said cellulosic fibers by said cross linking agent to produce a flat drying fabric, the total amount of water present during the reaction being not more than 100% of the weight of the dry fabric.

10. A process for imparting flat drying properties to a textile fabric containing at least about 40% cotton fibers so that the fabric will have a Hat and pressed appearance after washing which comprises applying to the fabric from about 20% to 100% of the weight of the cotton fibers of an aqueous solution of an alkali metal hydroxide, the amount of said alkali metal hydroxide, on a dry weight basis and calculated as NaOH, constituting not less than about 2% by weight and not more than about 15% by weight of the total water present, and from 6% to 30% by weight of the cotton fibers of epichlorohydrin and retaining the fabric in a flat condition for a time sufficient to effect enough cross linkages of said cellulosic fibers by said cross linking agent to produce a flat drying fabric, the total amount of water present during the reaction being not more than 100% of the weight of the dry fabric.

11. A process for imparting flat drying properties to a textile fabric containing at least about 40% cotton fibers so that the fabric will have a flat and pressed appearance after washing which comprises applying to the fabric from about 20% to 100% of the weight of the cotton fibers of an aqueous solution of an alkali metal hydroxide, the amount of said alkali metal hydroxide, on a dry weight basis and calculated as NaOH, constituting not less than about 2% and not more than about 15 by weight of the total water present, and from 6% to 30% by weight of the cotton fibers of a compound of the formula:

0 0 charm-on on,

and retaining the fabric in a fiat condition for a time suflicient to effect enough cross linkages of said cellulosic fibers by said cross linking agent to produce a fiat drying fabric, and total amount of water present during the 14 reaction being not more than of the weight of the dry fabric.

12. A process for imparting fiat drying properties to a textile-fabric consisting essentially of-cotton so that the fabric Jwill have a flatand' pressed appearance after washing which comprisesapplying to the dry fabric from about'30% to 100% of the weight of the dry fabric of an aqueous solution of an alkali metal hydroxide, the amount of said alkali metal hydroxide, on a dry Weight basis and calculated as NaOH, constituting not less than about 2% by weight and not more than about 15% by weight of the total water present, and thereafter applying to the fabric from 6% to 30% of the weight of the dry fabric of epichlorohydrin and retaining the fabric in a flat condition for a time suflicient to effect enough cross linkages of the cotton fibers by the epichlorohydrin to produce a flat drying fabric, the total amount of water present during the reaction being not more than 100% of the weight of the dry fabric.

13. The process of claim 12 wherein the aqueous solution of an alkali metal hydroxide is aqueous sodium hydroxide and the fabric is retained in a flat condition at a temperature of from 20 C. to 60 C. under such conditions as to prevent substantial loss of moisture.

14. The process of claim 12 wherein the aqueous solution of-an alkali metal hydroxide is aqueous potassium hydroxide and the fabric is maintained at a temperature of from 20 C to 60 C. under such conditions as to prevent substantial loss of moisture.

15. -A process for imparting fiat drying properties to a textile fabric consisting essentially of cotton so that the fabric will have a flat and pressed appearance after washing which comprises applying to the dry fabric from 30% to 100% of the weight of the dry fabric of an aqueous solution of an alkali metal hydroxide, the amount of said alkali metal hydroxide, on a dry weight basis and calculated as NaOH, constituting not less than about 2% and not more than about 7% by weight of the total water present, and thereafter applying to the fabric from 6% to 30% of the weight of the dry fabric of epichlorohydrin, and retaining the fabric in a fiat condition in a roll and in a container impervious to moisture, at a temperature from 20 C. to 60 C. for a sufficient time, at least 10 minutes, to effect enough cross linkages of the cotton fibers by the epichlorohydrin to produce a fiat drying fabric, the total amount of water present during the reaczion being not more than 100% of the weight of the dry I abric.

-1 6. A process for imparting fiat drying properties to a textile fabric consisting essentially of cotton so that the falbric will have a flat and pressed appearance after washing which comprises applying to the dry fabric from 30% to 100% of the weight of the dry fabric of an aqueous solution of an alkali metal hydroxide, the amount of said alkali metal hydroxide, on a dry weight basis and calculated as NaOH, constituting not less than about 5% and not more than about 15 by weight of the total water present, and thereafter applying to the fabric from 6% to 30% of the weight of the dry fabric of a mixture of 1,3- dichloropropanol and 2,3-dichloropropanol, and retaining the fabric in a flat condition in a roll and in a container impervious to moisture, at a temperature from 20 C. to 60 C. for a suflicient time, at least 10 minutes, to effect enough cross linkages of the cotton fibers by the mixture of 1,3-dichloropropanol and2,3-dichloropropanol to produce a flat drying fabric, the total amount of water present during the reaction being not more than 100% of the weight of the dry fabric.

17. A textile fabric, whenever produced according to the process of claim 1.

18. A textile fabric, whenever produced according to the process of claim 9.

19. A textile fabric, whenever produced according to the process of claim 12.

(References on following page) "1 5 Y 7 References Cited in'the file of this patnt FOREIGN PATENTS 510,511 fGreatBritain Aug. 2, 193 UNITED STATES PATENTS 724x296 Gre a-t Britain Feb. 6, 1955 1,741,637 Lilienfeld "Dec, 31, 1929 99 France ---'----SBP1- 5, 1951 2,264,229 Wallach Nov. 25, 1941 5 2 OTHER REFERENCES 2,524,399 Schoene Oct. 3, 1950 Reeve t 51.: Textile Research Jounial, 1955, p. 44. 

1. A PROCESS FOR IMPARTING FLAT DRYING PROPERTIES TO A CELLULOSIC FABRIC WHOSE CELLULOSIC FIBERS HAVE AN AVERAGE OF AT LEAST ABOUT 1.8 FREE HYDROXY GROUPS PER GLUCOSE UNIT WHICH PROCESS COMPRISES APPLYING TO SAID FABRIC A TOTAL AMOUNT OF WATER EQUAL TO AT LEAST 15% BUT LESS THAN 130% BY WEIGHT OF THE DRY WEIGHT OF THE FABRIC, A STRONG BASE SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL HYDROXIDES, ALKALI METAL SALTS WHICH FORM ALKALI METAL HYDROXIDES IN AQUEOUS SOLUTION, AND QUATERNARY AMMONIUM HYDROXIDES, THE AMOUNT OF SAID BASE, ON A DRY WEIGHT BASIS AND CALCULATED AS NAOH, CONSTITUTING NOT LESS THAN ABOUT 2% BY WEIGHT AND NOT MORE THAN ABOUT 15% BY WEIGHT OF THE TOTAL WATER PRESENT, AND AT LEAST ABOUT 5% BUT NOT MORE THAN ABOUT 30% BY WEIGHT OF THE CELLULOSIC FIBERS OF A CELLULOSE CROSS LINKING AGENT SELECTED FROM THE GROUP CONSISTING OF THOSE CAPABLE OF BEING REPRESENTED BY ONE OF THE FORMULAE: 